[Feature Request] Improve Formula parsing/printing consistency

[kMutagene]

Is your feature request related to a problem? Please describe.
the input of Formula.parseFormulaString and the output of Formula.toString are inconsistent:

let CO2 = Formula.parseFormulaString "CO2" // Number is an integer and no space between the elements

Formula.toString CO2 // val it : string = "C1.00 O2.00 " Number is a float and theres a space between the elements

while the output of the Formula.toString is valid input for Formula.parseFormulaString, i dont understand why we need the spaces and floats.

Additionally, (CO)2 is not parsed correctly (this case is marked as To-Do in the source code):

let C2O2 = Formula.parseFormulaString "(CO)2" 

Formula.toString CO2 // val it : string = "C1.00 O2.00" , expected "C1.00 O2.00"

Describe the solution you'd like
Solve the (CO)2 problem, change number output of Formula.toString to int and remove spaces

Describe alternatives you've considered
Formula.toString output is not wrong per se, so we could leave it as-is, but the (CO)2 problem needs fixing